Reading all the wonderful things the new ProGuard Improvements for Android do, I switched to to the new scheme by uncommenting the following line in a newly created
New Projects or old ones converted when changing API now in project.properties link to
proguard.config=${sdk.dir}\tools\proguard\proguard-android.txt:proguard-project.txt
You can simply link your projects proguard config by commenting the line and adding
proguard.config=proguard-project.txt
to it.
Cheers.